As VLJ designs mature, makers hone cockpit ideas

 - December 10, 2007, 9:22 AM

The new breed of very light jets (VLJs) now under development could turn out to be the biggest catalyst for business aviation growth since Bill Lear’s halcyon days in Wichita. But with cost, reliability and ease of use foremost in the minds of VLJ developers, the digital cockpit systems in these pintsize business jets of tomorrow will be unlike anything most pilots have seen.

While the possibilities are tantalizing, the marriage of advanced avionics technology with high-performance airplanes does present some serious potential pitfalls.

The goal of VLJ developers and avionics manufacturers seems simple enough: design a cockpit that is highly capable, easy to operate and tailored to the needs of the typical owner-pilot moving up from current-generation piston twins and turboprops. The major challenge, however, lies in providing VLJ pilots with all the information they need to complete the mission safely without overloading them with too much information or irrelevant information. This is an especially important consideration for small personal jets in the VLJ category since a single pilot, often a non-professional, will typically be at the helm.

At this stage, the Eclipse 500 and Cessna Citation Mustang are generally regarded as the early frontrunners among would-be VLJ contenders. As Eclipse and Cessna prepare for rigorous flight-test regimens beginning this year and continuing through next year, a clearer picture of the avionics packages the manufacturers have selected for each airplane is starting to emerge. Not surprisingly, both the Eclipse and Mustang cockpits include big, colorful LCD flight and multifunction displays (MFDs) and an assortment of standard equipment. While it is far too early to say which cockpit design is “better,” the differences between the Avio system in the Eclipse 500 and the Garmin G1000 system selected for the Mustang are worth exploring.

Eclipse 500 and Avio
The Eclipse 500 recently returned to flight testing after an engine supplier switch from Williams International to Pratt & Whitney Canada. The airplane that is flying now, N503EA, includes a complete version of the Avio integrated avionics system and an early software version that will evolve as tests continue.

Avio is a collaborative effort among Eclipse, Avidyne and several component suppliers. The cockpit is based on a version of Avidyne’s Entegra cockpit and includes a Meggitt/S-Tec autopilot; FreeFlight WAAS GPS receivers; Honeywell RDR-2000 weather radar; an Eclipse-developed autothrottle system and other avionics equipment one would expect to find on an airplane in this category.

According to Matt Brown, Avio product manager for Eclipse, the brains of the system are its dual computers, which send command signals to every system in the airplane through the electrical power distribution system (EPDS). In addition to the avionics, Avio controls and monitors virtually every other system on board the airplane, including the cabin and cockpit environmental controls, flaps and landing gear, the Fadec controls on both engines and even cabin lighting.

Major components of Avio consist of existing sensors and avionics from a number of well known companies. Harco, for example, supplies dual RVSM-compliant air-data computers, and the Eclipse 500’s dual attitude heading reference system (AHRS) comes from Crossbow.

The driving philosophy behind Avio has been to make the avionics wherever possible serve as a digital second crewmember, Brown said.

“When we sat down and started developing Avio, the approach was to make sure we were presenting the pilot with information, not just data,” Brown said. “This airplane is so automated and has the capability to deliver so much data that we really have to filter what’s offered to the pilot.”

An example of Eclipse’s “virtual copilot” design philosophy, Brown said, is the airplane’s smart checklists, which monitor various systems to make sure functions have been completed properly and alert the pilot if anything has been missed.

The standard EFIS setup in the Eclipse 500 includes dual primary flight displays (PFDs) and a single MFD. The PFDs in their standard setting show the usual flight-related information, but the pilot can rearrange data depending on preference. In normal operations, the MFD will display the moving map, EICAS data, standby ADI, optional class-B terrain warning, traffic, weather, systems-based synoptics, flight management pages and all electronic checklists.

Interestingly there are no mechanical backup instruments in the Eclipse 500. Instead, Avio has been designed for complete systems redundancy, meaning that anything that is shown on the MFD can also be displayed on the PFD and vice versa.

Unique to Avio is an Eclipse-designed keyboard that can be used for a variety of functions, including flight plan inputs on the FMS. A single keyboard on the left side is standard and a second keyboard is available as an option. All functions of Avio can be performed without the keyboard using rotary knobs and soft keys on the display bezels. This means the airplane can be dispatched with the keyboards inoperative, Brown said.

Optional equipment offered in the Eclipse 500 will include L-3 Stormscope; L-3 Skywatch; ADF receiver; DME; class-B TAWS; WAAS approach capability; and, at some point in the future, ADS-B. Eclipse may also offer XM satellite weather in addition to the standard Orbcomm weather datalink system, as well as upgrades for improved functionality, which could include a synthetic vision flight display, Brown said.

Citation Mustang and G1000
The Garmin G1000 cockpit for the Mustang features a 15-inch multifunction flat-panel display in the center of the instrument panel and a pair of 10-inch PFDs on either side. Unlike the team of suppliers that is piecing together the Eclipse cockpit, Garmin is supplying almost everything for the Mustang, including the autopilot, FMS, weather radar, terrain awareness and warning system (TAWS), traffic information system (TIS), solid-state AHRS and air-data computers.

According to Russ Meyer III, Mustang program manager for Cessna, specifications from Garmin call for the airplane’s front office to include a long list of standard equipment, including dual integrated radio modules, WAAS-capable IFR GPS receivers, RVSM-compliant air-data computers, mode-S transponders, dual AHRS, three-axis digital autopilot, TIS traffic, weather radar, EICAS and Garmin’s class-B TAWS.

The airplane’s FMS will be based on the GNS 430/530 platform, but with enhancements that include an FMS-style keypad in the center of the panel near the thrust-lever quadrant.

“For any pilot familiar with the GNS 430 and 530 from Garmin, managing the G1000’s flight management functions should be very straightforward,” Meyer said.

For the Mustang, Garmin will offer an updated version of the earlier Bendix/King KWX 58 X-band weather radar, a design it acquired a few years ago from Narco. From a mechanical standpoint the radar is the same as the original KWX-58, but its electronics have been redone. The 28-volt radar system uses a 10-inch flat-plate antenna and weighs about 10 pounds. It is TSO’d to 50,000 feet and a maximum range of 320 nm. Besides weather radar, the G1000 system is also equipped with a GDL69 datalink receiver capable of picking up XM weather.

The G1000 PFD has a wide-view artificial horizon with V-bar indicator and an HSI in the pilot’s choice of arc mode or full display at bottom center. Vertical tapes on the left and right read out airspeed and altitude, leaving room for a miniature moving map and a real-time nearest-airport display. A number of soft keys on the bottom portion of the display are used for setting up the display and entering necessary data.

True for pilots of all airplanes in the VLJ category will be a requirement for top-caliber training, including classroom instruction and hands-on time in full-motion simulators. Cessna plans to offer training in Independence, Kan., where it will manufacture Mustangs. In addition to the usual coursework, Cessna plans to give special additional instruction on the G1000 avionics with a focus on flight planning and FMS operation, Meyer said.

Eclipse, meanwhile, announced late last year that it has formed a training alliance with United Airlines. The plan is for training to take place at the United Flight Training Center in Denver using full-motion simulators and conforming with a curriculum co-developed by United and Eclipse. Buyers of Eclipse 500s will first undergo an initial flight skills assessment followed by supplemental training, if required. A self-paced computer-based study program is then provided, followed by unexpected-situations hands-on training, the type-rating transition course and a post-certification mentoring program.